This invention relates to a bead wire winding device which can be suitably applied in order to directly wind and dispose a bead wire at a predetermined position of a tire during molding on a rotatable molding support body.
When a tire is molded on a molding support body, for example a cylindrical drum or a core body with an external ring shape corresponding to an internal surface shape of a product tire, a bead wire is arranged at a predetermined position of a tire side portion during molding. This positioning is normally performed by attaching a bead ring, which is wound and formed in advance in a ring shape of a predetermined dimension by a bead fabricating device, to a side portion of a tire by a manual operation of an operator or by using a device called a bead setter.
Therefore, according to the prior art, until various types of bead rings which are fabricated in advance are used, space is needed to sort and store them or the like, and a number of operational processes are needed. Needless to say, when a bead ring is arranged by a manual operation, it is difficult to reliably realize highly accurate arrangement. Meanwhile, when a bead ring is arranged by using a bead setter, arrangement accuracy can be improved. On the other hand, it is necessary to provide a bead setter in addition to a bead fabricating device, so equipment cost becomes high, and there is a problem such that the number of operations to mount a bead ring onto the bead setter becomes high. Furthermore, when a plurality of bead rings are arranged in each side portion of tire by a conventional bead setter, a number of operations are needed to hold each bead ring onto the bead setter. In addition, there is a high possibility that plastic deformation will be generated in a bead ring while the bead ring is handled, and there is a problem such that deterioration of tire quality cannot be avoided.
That is, a conventional bead setter, shown in a perspective view of FIG. 10, sets a plurality of bead rings in each side portion of a tire during molding. This conventional bead setter sets two circular bead rings or more, which have the same diameter and are formed of steel cords, in advance at predetermined positions of each side portion during molding of a heavy load-use tire used for a truck, bus, or the like. Prior to setting, each bead ring is engaged and held by a manual operation of an operator at the tip of cylinder setters S1 and S2, respectively, which approach and withdraw from respective side portions of a tire T in a horizontal direction during molding. Because of this, when two bead rings or more are respectively set at each side portion of a tire during molding, there is a problem such that the number of operation processes become high because the operation of securing a bead ring in each cylinder setter S1 and S2 has to be performed at least twice.
Incidentally, when a bead ring is thus set, an external diameter of the tire T becomes larger than an internal diameter of the bead ring from the beginning of the molding or during the molding. Therefore, particularly, prior to molding a tire, it is necessary to hold or support a predetermined number of bead rings, for example two bead rings, in advance on the cylinder setter S1 which is arranged in a rotary driving portion of the tire T. Because of this, in a conventional cylinder setter S1, as shown in an enlarged perspective view and a plan view of FIGS. 11a and 11b, respectively, a tip holding portion H which has an external diameter substantially equal to an internal diameter of a bead ring is provided to engage the first bead ring that is initially set at a side portion of the tire T. At the same time, a space SK is provided to temporarily store a second bead ring which is set next. This space SK is positioned behind two diametrically opposed flanges F, at upper and lower positions in the figure.
Here, arrangement of the second bead ring to the space SK is shown in FIG. 12a. A bead ring B1 is elastically deformed in a substantially longitudinally elliptical shape. First, the lower end portion is passed around the lower side of the lower end side of the flange F and engaged in a notch N disposed under the space SK, as shown in FIG. 12b. Subsequently, the upper end portion of the bead ring B1 is made to pass over and behind the top end side of the flange F, as shown in FIG. 12c. Then, an external force which operates the bead ring B1 is removed, and the bead ring elastically recovers into a ring shape and is supported by a tube shape portion of the space SK. Furthermore, arrangement of the first bead ring to the tip holding portion H is performed as the bead ring is maintained in a ring shape as-is and engaged by the circumference of the tip holding portion H.
Therefore, as the first bead ring which is initially set in a side portion of the tire T is set while maintaining its initial ring shape, there will be no particular problem. However, there is a high possibility that undesired plastic deformation will occur in the second bead ring B1 each time it is arranged in the space SK as described above, and each time it is removed from the space SK, due to the deliberate deformation into a substantially elliptical shape. There was a serious problem such that it was substantially impossible to accurately set the bead ring B1 at a predetermined position, due to this plastic deformation.
This invention was made to solve the above-mentioned problems in the prior art. An object of this invention is to provide a bead wire winding device which can accurately arrange a bead wire at a predetermined position with few operations without increasing equipment cost and causing undesired plastic deformation to a bead wire. Another object is to eliminate the need to pre-manufacture and store various types of bead rings in which a bead wire is wound and formed in a ring shape, and to completely eliminate the need for space and numerous operations to sort or store the bead wires.
A bead wire winding device of this invention is provided with a molding support body connected to a rotational shaft, a winding guide(s) which is rotated with the molding support body, and which approachingly and retreatingly displaces with respect to each side portion of the molding support body and enlargingly and reducingly deforms, and a wire supply means which supplies a bead wire to a wire seating portion of the winding guide within a space defined by each winding guide which is in an approached state with respect to a respective side surface of the molding support body, and in an enlarged diameter state. The winding guide is constituted by a plurality of radially displacing members, which can be displaced in a radial direction, connected to a boss portion through link members. Each of the radially displacing members has a protrusion that is located radially inward an outer periphery of the respective radially displacing member and which forms a wire seating portion. Furthermore, an advance/retreat driving means of a boss portion is disposed that advancingly and retreatingly drives the boss portion with respect to the molding support body. A clamping claw is provided on at least one of the radially displacing members, and is urged constantly in a closing direction and pinching a tip portion of the bead wire. A driving means is disposed which causes opening displacement of the clamping claw.
According to the above-mentioned structure of a bead wire winding device of this invention, regardless of whether the molding support body is a conventionally known flat molding drum or a core body with an external ring shape corresponding to an internal surface shape of a tire, a winding guide is made to approach and be positioned at a side portion of the molding support body. By winding a bead wire in an enlarged-diameter state on a side surface of a molding support body, that is, within a space bounded by a winding guide and a tire side surface during molding, it is possible to directly and accurately dispose a bead wire at a predetermined position at each side portion of a tire during molding when a molding operation of the tire is performed.
Therefore, according to this invention, it is possible to sufficiently prevent problems related to numerous operations, occupied space, equipment cost, bead rings, that is, deformation of bead wires, and the like that arise in pre-fabricating ring-shaped bead rings.
Furthermore, in the above-mentioned device, a radially displacing member can be constituted by a fan-shaped member or a circular arc-shaped segment, or a rod member, in which a peripheral width is far narrower.
Preferably, an advance/retreat driving means of a boss portion and a driving means of a clamping claw are fixed to respective non-rotational side members. In this case, the weight of rotation members which are rotated and driven with the molding support body can be advantageously decreased, and a power supply structure to the driving means can be simply performed.
Preferably, the molding support body can be removed from a rotational axis, and, for example, the molding support body can be separated from the rotational axis while remaining integral with a green tire formed thereon. In this case, the molding support body can function as-is as an internal surface type within a vulcanizing mold, and a process of separating the green tire from the molding support body is not needed.
Preferably, the wire supply means is constituted by a reforming roll which bends and deforms a bead wire which has been fed out, a grooved roll which specifies a winding position of the bead wire after it goes through the reforming roll, and a pressing roll which presses a trailing end portion of the bead wire after it goes through the grooved roll. In this case, between the grooved roll and the pressing roll, it is preferable that a cutter be disposed to cut a bead wire which has been wound over a predetermined length.
Preferably, the wire supply means can be displaced in an axial direction of the rotational axis during the operation. The displacement in the axial direction is a displacement with a pitch equivalent to a thickness of the bead wire.
Furthermore, the displacement of a radially displacing member of a winding guide in a radial direction, based upon the operation of a link member, can be performed as follows, for example. When a boss portion is moved toward a molding support body along the rotational axis, each radially displacing member is slid in a radially outward direction on an inclined cam surface disposed on the rotational axis. When the boss portion is moved in the reverse direction, each radially displacing member is slid in a radially inward direction on the inclined cam surface. However, more preferably, a base tube that rotates and a boss portion are sequentially arranged on the rotational axis, and the base tube and the boss portion can be mutually independently displaced in an axial direction of the rotational axis. A guide means which guides displacement of a radially displacing member in a radial direction, for example, a rail and a direct moving guide formed of a slider engaged with the rail, is provided on each radially displacing member, and on a flange disposed at the end portion of a molding support body side, of the base tube.
According to this, within a surface perpendicular to the rotation axis, displacement can be smoothly and accurately performed while maintaining the radial displacing member at a predetermined position. In addition, fixing of a cam member or the like on a rotational axis is not needed, and removing and fixing of a structural member of the device to a rotational shaft can be easily performed.
Additionally, this invention proposes a method of winding a bead wire which can be suitably obtained by using a winding device which is structured above. In a method of winding a bead wire of this invention, prior to arranging a bead wire which is made to rest against a side portion of a molding support body, that is, a tire molded on the molding support body, in a radial direction and a circumferential direction, the bead wire is wound a predetermined number of levels on a wire seating portion protruding toward the molding support body of the winding guide within a space defined by the molding support body and the winding guide which is in an approached state with respect to a respective side surface of the molding support body, and in an enlarged diameter state. After completion of winding the bead wire, the winding guide is made to be distant from the molding support body in a reduced diameter state and the bead wire is maintained at a required position of the molding support body.
According to this invention, by winding a bead wire when a molding operation of a tire is performed, it is possible to directly and accurately arrange a bead wire at a desired position without having an unexpected deformation, and efficiency of the operation of arranging a bead wire can be significantly improved.